Surface characterization of sulfated zirconia and its catalytic activity for epoxidation reaction of castor oil

Abstract

The solid acid catalysts SO₄²⁻/ZrO₂ were prepared by impregnation technique at different calcination temperatures. The surface characterizations were carried out by using scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), temperature programed desorption of NH₃ (NH₃-TPD), and N₂-BET. The SEM results showed that the size of the SO₄²⁻/ZrO₂ was not uniform and varied from about 1 to 20 µm. The characteristic peaks in FTIR spectra were essentially the same within the calcination temperature range of 400–700 °C. The XRD results indicated that the transition temperature from amorphous to tetragonal phase was up to 500 °C. The strong acid and superacid sites of the samples could be observed by the NH₃-TPD results. The largest BET surface area was 140 m²/g, when the calcination temperature was at 500 °C, and all the pore size distributions belong to mesoporous range. The solid acid SO₄²⁻/ZrO₂ was used for the epoxidation of castor oil. When the calcination temperature of SO₄²⁻/ZrO₂ was 600 °C, reaction temperature 45 °C, and reaction time 8 h, the reaction effect was better with an iodine value of 33.0 ± 1.6 g/100 g and an epoxy value of 2.45 ± 0.11 mol/100 g.

Keywords::

• BET
• Epoxidation
• FTIR
• NH3-TPD
• SEM
• SO₄²⁻/ZrO₂
• XRD

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Financial support for this work from the National Natural Science Foundation of Ningxia (NZ17094), National Natural Science Foundation of China (21266001), State Key Laboratory of Chemical Technology (2016HG03), the State Key Laboratory of Civil Committee Chemical Technology, Ningxia low-grade resource high value utilization, and environmental chemical integration technology innovation team project are gratefully acknowledged.